Receiver-hook switch



J. T. GRAY.

RECEIVER HOOK SWITCH.

APPLICATION FILED AUG,13, 1919.

Patented Aug. 23, 1921.

glvwe 71 km 570]??? 776m l I 2 Z7 26 fly 5 UNITED STATES JOHN T. GRAY, OF GREAT FALLS, MONTANA.

RECEIVER-HOOK SWITCH.

Application filed August 13, 1919.

To all whom it may concern:

lie it known that I, J OHN T. GRAY, a citizen of the United States, residing at Great Falls, in the county of Cascade and State of Montana, have invented certain new and useful Improvements in a Receiver-Hook filwitch, of which the following is a specification.

This invention relates to telephony and more particularly to receiver hook actuated switches for telephone sets.

The invention has for the primary object to provide an improved switch structure wherein maximum opening movement is transmitted to the relatively movable contact members of the switch upon replacement of the telephone receiver to provide an adequate air gap preventing lightning or other electrical discharges from reaching and affecting the talking circuits.

With these and other objects in view, the invention consists in the novel. construction, arrangement, and combination of parts as will be more fully described hereinafter, reference being now made to the accompanying drawing in which:

Figure 1 represents a fragmentary sectional view of a telephone set illustrating the improved switch and receiver hook applied thereto.

Fi 2 represents a side elevation of the switch.

Fig. 3 represents a top plan view of the switch and arm.

Fig. i represents a. sectional view similar to Fig. 1 illustrating the receiver hook in elevated position and the switch closed.

Fig. 5 represents a fragmentary sectional view of a portable desk telephone illustrating the invention applied. thereto.

Referring to the drawing in detail, the numeral 1 indicates a fragment of the casing in which the usual telephone set is inclosed, the wall of the casing being provided with a slot 2, accommodating the arm or shank portion of the receiver hook 3 which is mounted for swinging movement in a vertical plane upon a pivot pin 4. The exposed terminal of the hook is of the usual bifurcated type in order to receive and support the receiver but the inner extremity of the arm or shank of the hook is extended a distance beyond its pivotal axis 4 and is bifurcated to receive a rotatable bar roller 5.

The switch is mounted upon a base plate ti formed of insulating material in order that Specification of Letters Patent.

Patented A11 23, 1921.

Serial No. 317,232.

the switch may be conveniently applied to various types of telephone sets. A plurality of posts 7 constructed of conducting material are mounted adjacent and parallel to one edge of the plate and are connected with electrical connectors whereby the terminals of the wires of the telephone circuits may be connected therewith. Switch arms 9 correspending in number to the number of supporting ears 7 are iivotall r' secured thereto and maintained in uniformly spaced and parallel relation by an insulating bar 10 with which the terminals of the arms are connected.

A series of contact posts 11 is secured adjacent the edge of the base plate 6 opposite the supporting posts 7 and are adapted for engagement by the spring contact members 12 carried by the several arms 9 under which the posts 11 are arranged. Springs 13 having the medial portions 14. looped about the axes of the arms 9 are secured terminally to the arms and to the supporting ears 7 and their arrangement is such. as to normally tend to swing the arms and engage the yieldable spring contact members 12 with the posts 11 and thereby electrically connect these elements.

A laterally projecting cam block 15 is secured to the insulating bar 10 disposed opposite and normally in contact with the bar roller carried by the pivoted receiver hook. The toe of the cam block 15 is preferably curved as indicated at 16 for sliding contact with the roller 5 and in the preferred or rangement of the switch the axis of the pivoted arms 9 is preferably at right angles to the axis l of the receiver hook.

As stated, the tension of the springs 1.3 normally tends to move the pivoted arms 9 toward the base plate (3 and owing to the arrangement, of the cam block above the inner terminal of the receiver hook shank the outer terminal of the latter, when re. lieved of the weight of the receiver, is elevated due to the depression of its inner tee minal, incident to the sliding contact of the roller 5 with the cam block 15. Upon depres sion of the inner terminal of the hook shank. the spring contact members 12 are brought into engagement with the relatively stationary contact posts 11 thereby closing the talking circuit through the usual condueductors (not shown). However, when the receiver is replaced upon the hook 3, its weight overcomes the tension the springs 13 and the roller 5 acting upon the cam block 10 swings the several arms 9 outwardly thereby spacing the spring contact members 10 a suflicient distance from the posts 11 to prevent injury to the talking circuit by lightning or other electrical dischar es. In the-modification of the invention illustrated in Fig. 5, the switch is shown as applied to the receiver hook of a conventional type of portable desk telephone. Referring to this figure in detail the numeral 20 indicates the usual supporting base carrying the hollow upright or standard 21 in which the shank of the receiver hook 22 is pivotally 'mounted at 23. A supporting plate 24 of insulating material is mounted internally of the hollow base 20 and is provided with a series of depending supporting ears 25'pivotally-supporting the switch arms 26. The opposite terminals of the arms are connected by an insulating bar 27 and springs 28 are connected with the arms whereby the latter are normally urged upwardly to cause engagement of the spring; contact members 29 carried thereby with the relatively stationary contact post- 30 adequately mounted upon the base 24.

Intermediate the receiver engaging terminal of the hook 22 and the pivotal axis 23 thereof, a depending rod 31 is secured to the receiver hook, extends outwardly through the hollow upright 21 and the supporting plate 24 and is engaged upon the cam block 32 carried by the insulating bar 27.v The tension of the. several springs 28 normally tends to elevate the arms 26 and due to the engagement of the terminal of the rod 31 upon the cam block 22 and connection oi I said rod 31 with receiver hook 22, the latter is automatically elevated upon removal of the receiver causing engagement of the spring contact members 29 with the post 30 thereby closing the talking circuit of the telephone.

From the foregoing it is evident that the throw or o ening movement transmitted to the switch y the receiver hook is .increased. to such extent as to provide a maximum air gap bet-ween the contacting elements of the switch, when the receiver is replaced, thereby insuring against injury to the conductors and instruments of the telephone system and consequent loss and damage by shock and fire to persons and property adjacent to the telephone incident to overloading of the line byexcessively high electrical currents frequently encountered during electrical storms and by interference with external sources of high tension currents. It is also evident that the extent of movement of the switch and the consequent length of the air gap may be readily varied to meet widely different conditions by simply varying such mechanical details of the structure as the inclination of the cam block or the length of the switch actuating terminal of the receiver hook.

lVhat I claim is 1. A receiver hook switch for telephones comprising a pivoted receiver hook, fixed contacts, interconnected switch arms cooperating with said fixed contacts and a cam for actuating said switch arms, said cam being disposed in the path of the inner end of the receiver hook and operable thereby to correspondingly close and open the circuits controlled by the switch.

2. The combination with a telephone switch, a casing, a pivoted receiver hook, a switch base secured to the inner face of the wall of the casing adjacent the inner end of said receiver hook, a switch blade pivotally supported on said switch base and a cam carried on said switch blade and arranged in the path of movement of. the inner end of said receiver hook and operable thereby upon the raising and lowering movements of the same, whereby to correspondingly close and open the circuit controlled by the switch.

3. A receiver hook switch for telephones comprising a casing, a pivoted receiver hook extending through an opening in the wall of said casing, a fixed base plate secured to the inner wall of said casing adjacent the said opening, a plurality of interconnected spring controlled switch arms pivoted to said base plate at right angles to the receiver hook. a cam secured to one side of the connected switch arms and directly in alinement with the opening in the casing. and a cam roller carried by the inner free end of the receiver hook in the path of and in constant engage ment with the cam during the raising and lowering movements thereof as the circuit controlled switch is opened or closed upon the corresponding movement of the receiver hook.

In testimony whereof, I afiix my signature hereto.

JOHN T. GRAY. 

